I'm dying wood veneers, and I need to be able to match various colors. I've done some experimenting, and it seems clear that mixing colors to get a particular value, shade, and tint is not a simple matter of proportional combinations of colors. For example, combining yellow and grass-green to get a pale lime green, 10:1 Y:G or 15:1 seems to be needed for a color about midway between the two. I can experiment, of course, but it's fairly tedious; I'm hoping for some info to save some time.

So, questions: are there any guidelines on which colors and proportions to use for various results? Are there a particular 3 colors which could be considered the "primaries" to combine according to the usual CMY system? Others that would be the secondaries?